Telephone-exchange system



Sept. 28,1926.

E. S. GIBSON TELEPHONE EXCHAEGE SYSTEM Origipal Filed June 27, 1924 10 Sheets-sheaf l W e/772R v fhr/ J? 67 550 by WQ W E48. GIBSON- TELEPHONE EXCHANGE SYSTEM Original Filed June 27, 19,24

Sept. 28 1926.

QM N lnvenfan' fdr/ J. 6/.6s0/2 Sept. 28,1926. 1,601,064-

E. S. GIBSON TELEPHONE EXCHANGE, SY STEM Original Ffiled June '27,. 1924 10 Sheet-Sh'eti .3

Sept.- 28,1926. 1,601,064

' E, s. GIBSON,

TELEPHONE EXCHANGE SYSTEM 7 Original Filed June 27. 1924 i0 Sheet-Sh'et' 4 Sept. 28 1926. 1,601,064

E. s. GIBSON TELEPHONE EXCHANGE SYSTEM Original Filed June 27, 1924 10 sheetg-shf 5 E. s.. guasom TELEPHONE EXCHANGE SYSTEM Original Fileq' June 27, 1924 10 Sheets-Sheet 6 Sept. 28 1926.

Sept. 2a, 1926. 1,601,064

E. s. GIBSON TELEBHONE EXCHANGE SYSTEM Original Filed June 27, 1924- 10 Sheets-'Sht 7 Slepf. 28 19 26.

E. s. GIBSON TELEPHONE EXCHANGE SYSTEM Original File d June 27, 1924 1O Sheets-Sheet 8 Sept. 28,1926. 1,601,064

- E. 5. GIBSON TELEPHONE EXCHANGE .sY-TE Original FiledJupe 27. I924 1o sheets-she ve E. s. GIBSON TELEPHONE EXdHANGE SYSTEM- Original. Filed June 27, 1924 Mae/777K far/ J? 67km Patented Sept. as, rare.

EARL s. crrson, or arnenwoon, Newsa ent, Assrsncs ro wnsrsnn nLEcrRi'c 'ooIvrrANY, rncoaronarnp, or

NEW YGEK, N. Y., A CORPORATEON OF NEW YORK.

'rnr nr'roim-nxcrmnen SYSTEM.

Application filedrJune 27, 1924-. Serial No. 722,866.

This invention relates to telephone exchange systems, and more particularly to' systems employing automatic switching ap-- paratus in the extension of conversational connections.-

The object of this invention is to enable a 1 repetition of the testing of a group of lines or trunks due to'the fact that such group has been previouslytested and all lines or trunks there-in have been found unavailable. 7

'A feature of the invention relates to a system having a number of testing equipments, each arranged for connectionto a group of trunks outgoing from a selective switch, together withmeans for disconnecting from said group a testing equipment which has found all trunks therein busy, and for automatically connecting to such group either the same or another testing equipment for the purpose of making a repeated test of said trunks.

A further feature relates to a system in which'a sender is connected to one of a number of markers and the connected marker is then connected to a group of trunks, said markers each having means for making a test of said trunks, together with means for disconnecting the marker both from the sender and from the trunk group if all trunks are' found busy and for automatically connecting either the same or another marker both to said sender and to said group of trun rs to make a further test of said trunks.

Referring to the drawing, Figs. 1 to 10, inclusive, taken in the order illustrated in Fig. 11 disclose a portion of a central oilice telephone system incorporating the features of this invention.

Fig.1 shows schematically a subsc'ribers line, a. line switch, an outgoing trunk, a

sender selector switch, and a portion of a subscribers sender.

Fig. 2. shows a district selector switch in which terminate trunks leading from the line switches.

Fig. 8 shows an oi'lice selector switch to which trunks from the district selector switch lead and which has access to trunks outgoing to succeeding switches.

Fig. 4- shows a portion of one of a number of register senders.

Fig. 5 shows a multi-contact relay connect-ing device for associating the register senders with the markers.

Figs. 6, 7 and .8 illustrate one of a num- Renewed April 5, 1926.

her of controlling markers, the function of which is to determine the selective and-testing operation of the district and office switches. j Y 9shows a frame connector for connecting the markersto the frames of the district switches and also a trunk connector for associating the marker with the different groups of trunks outgoing from they dis trict switches. I

Fig. 10 illustrates a frame connector and a trunk j connector for the ofiice selector switches.

The system disclosed herein is an improvement' upon the type of system shown and described in the patent to S. B. WVilliams, No. 1,517,331, granted December 2, 1924:, and in the application of W. W. Carpenter, Serial No. 703,362, filed April 1, 1924, to which reference is hereby made for an understanding of the various operations which may hereinafter be referred to but not specifically described. I

In systems of this type where markers are associated with register senders and also with the particular selective switch at which the selective operation is to take place, and wherein the marker is provided with equipment for making a. test of the trunks in the selected group in order to ascertain an idle one before directing the operation of the switch to select such a trunk, it may frequently occur that the marker at the time of making the test finds that none of the trunks in the desired group is available. Heretofore, when this condition was encountered, it was impossible to proceed further with the establishment ofthe connection, and usually a busy signal was transmitted to the calling subscriber to advise him that the call could not be completed.

According to the present invention, however, if a marker at the time of making a test of the trunks in the selected group at any selective stage, finds all of the trunks to be simultaneously busy or otherwise not selective, it automatically releases from the register sender to which it is connected and also from the group of trunks to which it is connected. Thereupon, the sender immediately seizes either the same or another mark er and governs it in such a manner that it becomes associated with the proper selective switch and with the same group of trunks again for the purpose of making a repeated test to ascertain it, in the meantime, any one of such trunks has become idle. This procedure may be repeated a number of times until an idle trunk is found, or if after having made a predetermined number of repetitions no trunk is found to be idle, then the usual busy signal may be transmitted to the calling subscriber.

General description of the apparatus and of the operation.

' The calling subscribers lines, such as the line 100, terminate in vertical rows of contacts in coordinate line switches 101. hese switches have access to groups of trunks, such as the trunk 102, which extend and appear in vertical rows of contacts in coordinate district selectors. The trunk 102, for instance, appears in the vertical row 201 oi the district selector 200. Another trunk 211 similarly occurs in the vertical row of contacts 202, and still other trunks, of course, may be provided.

The district selector switch 200 contains a number of vertical rows of contacts 203. 20L etc, in which appear numerical groups of trunks outgoing to succeeding switches. The group occurring in the row 204:, for e2;- ample, contains trunks which lead to OfiiCG selectors 300.

The trunks incoming from the district selectors terminate in vertical rows ot contacts 301, 302, etc., of the coordinate o'ltice selectors 300. These ofiice selectors in turn have groups of trunks appearing in rows 303, 301-, etc., which lead out of the ()l'iiCB and to switches or other equipment in distant otfices.

Each of these coordinate switches comprises a plurality of intermediate or hori zontal links. together with vertical and horizontal selecting and operating" bars and individual magnets for operating these bars. The district switch 200, for example, has a number of links 205, 200, 207, 208, etc.. with individual operating bars 215, 210, 21. and 218 and the respective horizontal operating" magnets 2 .0, 220. 221 and Furthermore, the switch has vertical bars 200, 213, etc., together with corresponding operating' magnets 210, 211 and 212.

The otiice selector switches are similarly constructed including horizontal links 306 and 307, together with the horizontal bars and vertical bars and operating may;- nets.

The trunks such as 102. leading from the line switches to the district selector. also appear in coordinate sender sel ctor switches 108 which have access to a number of recording senders, one of which is shown partiall in Fig. 4 and Fig. 1.

The register senders appear in sender connecting devices 500, each different sender being represented by a different multi-contact relay 503, 50 1, etc. The device 500 is also provided with a number of relays 510, 512, etc., each of which represents a dillerent one of the controlling markers. By operating the proper pair of these relays, any sender may be connected to any marker.

The marker includes a number of registers 000, 001, and 602 which receive the o1- .tice portion of the entire designation, which is made up of three separate digits, from the register sender. Furthermore, a translating device 006 is made up of a number of sets of inulti-contact relays 010, (311, (512, etc, and cm, 614-, 615, cm, cos, 009, etc. The registers 000, 001., etc, cooperate with this translating: device in such a manner as to determine the selection of the group relays 712, 713. 71 1 715, etc. These group relays determine the particular groups of trunks at. the district and otlice switches which must. be involved to route the call in the direction corresponding to the designation transmitted to the sender.

The mark-er also determines the selection and operation of the proper one of the frame connectors 000 in order to associate itself with the group of district trainee 200 containing the frame in which appears the trunk over which the connection has been extended trom the calling line. This frame connector 000 includes a number of relays 002, 903, each individual to a different one of a plurality of markers. It also comprises a number of relays 004:. 905. etc.. each individual to a particular district frame 200 in the group. Relay 005. for instance. is individual to the frame 200 shown in the drawing.

(Ol1t10"t0i 001 compriFes a num- 910. .011 ea h di idual to a 'ihe (no. 901 in ada number a e 012. l "h o; In h is ndividual to r. litcronp oi t unk outgoing trmn the Frames. 20 he (it ea h v be to appear in as iraole.

. t e otiir'e frame conthe triril'v conne tor 1 l0 ill and u e a number oi corrcspontlinp; mult rclavs.

.1 ic l'er equ nped with a te tine de. 'e constituted of l"..' f gt in relavs 300. Th e lttrs serve o and the corre pond- :-t either in other lfit fl with the sele t an idle its corresponding id e link :m

it h tlic horizontal lii inn; ontg'oine' trunks ot an g oup the (liStsiJ't or the or I we r -:l distrutrunk and then they are su etpicntly associatiwl the proper oince switch to perform a simil-Jr function.

Another Function ot the marke is to Illtc mine from the ctiice code I(' i: l'1al'iu!! i the sender. the nawhich it receives: tr.

i of. a circuit extending baclr'into the s ture or class of the connection that is to be extended. This it does through the medium of the translator 006 and may cause "the operation of one-of a numoer 01? class relays 628. These class relays or the translator itself may directly cause the closure for the operation of the proper class re in the sender, thusgiving the sender necessary information to enable it to be prepared to exercise the neees ary control. over the-connection involved. ihe class relays in the marker may also cause the con-,-

pletion oft circuits leading throi horizontal link of the dish to operate certain relays located 11 circuit 102.

' The line switch 101, selector switches 200 and 300, and the sender sel ctor switch. 1 may be of the general construction and operation as those shown and described in the patent to C. L, Goodrum and J. ll. Reynolds, No. 1,515,735, granted November 18, 1924, and the patent to O D ll illiams, No.

o. 1). 1,517,331, granted December 2, Detailed description of the estabishmnt 07 a oomiccteon.

a special It will now be assumed for the purpose or describingthe invention that the subscriber of line 100 wishes to obtain a connection extending through the district and oilice selector'switches 200 and 800. The calling subscriber in initiating the call, causes the operation of line switch 101 to extend his line over an idle trunl: 102'to the district switch 200. The initiation of the call also causes the operation or the sender selectorswitch 108 to associate the trunk 102 with the idle register sender shown in the drawing. During the operation of the sender selector switch 108, a circuit is completed for operating the relay 10a. The relay 10% com pletes a holding circuit for the slow-release relay 106 which has been previously operated. This holoing circuit leads through the lower contact or r elay 104 and the locking contact of relay 100. As soon as the sender selector switch 108 and the line switcl 101 have operated, the subscribers lin is included in series with the impulse relay 400 in the sender. The circuit for this purpose may be traced from battery, through the right winding of relay 100, outer right contact of relay 410, thencethrough the sender selector switch 108 over the ring or the trunk 102, through the line switch 101 over the loop of the line 100, and returning through the line switch 101 and sender selector switch 108. inner right contact of relay 410, to ground through the right wind ing of balancing coil 103. Relay 4:00 operates and closes a circuit for the slow-release holding relay 401. Relay 01 completes operating circuits for the relays 102 and 116.

or release relay no, to ground at the inner left contact of relay 102. The relay "102 applies ground potential through its inner ft contact, left baclr contact oi relay 110, to the conductor 11?,which serves to hold the sender selector switch 108 and'th relay 10 1 in operated condition.

Recording the clcse'gnai'z'o'n in the emblem-- The subscriber new manipulates his (1 i (not shown) to transmit a. number of se ries of impulses representing the designation. The impulse relay sponds to these impulses and cooperates with relays 1:05, 4:06, 107, 108 with set or c unting relays diagrammatically illustrated by the rectangle 40-1 to cause the setting 01" a correspond 0' number 01" registers illus rated diagrann ,tically by the rectangle 109. The general runner in which the foregoing operations'inay be accomplished is described and illustrated in the patent to S. B. ll illiains, No. 1,517,331, granted Dec. 2,

est/i Association of sen-(Ker an idle ma-rlaer.-rs soon as the fir t hree sets or registers 109 have been operated, a circuit is closed extending over conductor 118, through the winding of relay 113, to battery. Relay 1 13 causes the energization relay 501 to initiate the operation or the connector 500. The circuit for this purpose may be traced. from battery, through the lower contact of relay 502, left winding of relay 501, conductor 513, contact of relay 4:11, outer right back contact of relay 114-, left contact of relay e13, conductor conductor 4121, to grouno at the outer contact of holding relay 116. Relay 501 operates and closes a holding circuit from battery, through the winding of relay 502, right front contact and right winding of relay 501, to ground over the circuit above traced. Relay 501 holds and relay op crates in this latter circuit. Relay 502 in operating, prevents the operation subsequently or another relay similar to the relay 501. lVith relay 501 operated. inulti-contact relay 503 is energized in a circuit from battery, through its winding, left contact or relay 501, upper contact of relay 505, to ground at the inner lower contact of relay 502. Relay 503 looks through its own con tact to ground at the up er contact or re lay 502;

Relay 502 completes a start circuit to select the first idle one of the markers; Assuming that the marker appearing in th, multi-contact relay 512 is busy and that the next marker illustrated is idle, this start circuit leads from ground, through the inner lower contact of relay 502, inner contact of relay 505, left front contact of relay 720, conductor 721, through the distributing frame 684, contact of relay 612, lower contact of relay 607, conductor 635, to ground at the outer right contact of relay 708. Re lay 714 looks through its own contact, conductor 722, inner right back contact of relay 706, to ground. at the contact of relay 700.

The relay 714 represents the group of trunks out-going from the oitice switch 300 in the desired direction, as for example the group appearing in the vertical-row 304. Relay 714, moreover, causes the operation of the district selector group relay 712 in a circuit from battery, through the winding of relay 712, contact of relay 714, middle right contact of relay 707, outer left contact of relay 708, to the grounded conductor Relay 712 represents the group of trunks appearing in the vertical row 204 of the district selector 200 which extend to the ofiice selector switch 300. 1

In case class information is necessary for the sender, the classrelay 686 may be operated in a circuit from battery, through its winding, contacts ofrelays 612, upper contactof relay 607, to the grounded conductor 635'.

Relay636 applies ground potential to conductor 638, which extends through the connector 500, thence over the conductor 520, through the winding of class relay 441 to battery. Relay 441 operates and locks to conductor 420 and later serves to govern the operation of the register sender in a manner suitable for theparticular class of call being extended.

Qpemte'on of the district frame con-nector.At-the time relay 604 operates, it closes an ei'iergizing circuit forthe relay 907 of the frame connector 900. This circuit may be traced from battery, through the outer right contact of relay 704, conductor 728, winding of relay 907, conductor 919, back contact of relay 725, conductor 726, outer right contact of relay 604, conductor 640, through the connector 500, conductor 110, right back contact of relay 422, conductor 423, thence over conductor 111, through the connector 500, to ground over conductor 719, as previously traced. Relay 907 completes a circuit for relay 906, traceable from battery, through the right winding of the latter rclay, front contact of relay 907, back contact of relay 920, (assuming this relay to be deenergized), upper cont-act of relay 909, to

ground at the back contact of slow-release relay 908. WVhen relay 906 has operated, it operates slow-release relay 908 in a circuit from battery, through the winding of relay 908, lower back contact of relay 909,, right contact of relay 9,06, conductor 921. conductor 922, outer left contact of relay 711, niiddle right contact ofrelay 707, outer left contact of relay 708 to the grounded conductor 722. The relay 908 operates and opens the operating circuit of relay 906. Relay 906 being slightly slow-to-release, however, remains energized until relay 908 has fully operated. A holding circuit for relay 906 is then closed from battery, through the left contact of relay 906, left back contact of re, lay winding of relay 909, to ground at the front contact .of relay 908. Relay 909 operates and opens the circuit ofrelay 908. Relay 908 releases and operates the multicontact relay 902. The circuit for this purpose leads from battery, through the winding of relay 902, outer left contact of relay 906, upper front contact of relay 909, to ground at the back contact of relay 908. Relay 909 being operated, prevents the 0p eation of another of the relays 906, 923, thereby avoiding interference by other markers. After relay 908 releases, relays 906 and 909 remain operated in a circuit which leads through the lower front contact of relay 909, right contact of relay 906, to the grounded conductor 921.

The vertical operating magnet 210 controlling the row of contacts 201 in the switch 200 in which appears trunk 102, is now operated, The circuit may be traced from battery, through the winding of said magnet, conductor 227, left back contact of relay 107, through the switch 108, conductor 112, connector 500, conductor 521, normalcontact of relay 708, inner left back contact of relay 710, conductor 727, contacts of the connector 900, outer left contact of relay 711, 1niddle ri 'ht contact of relay 707, outer left coutact of relay 708 to the grounded conductor 722. The magnet. 210 rotates the vertical bar 209 and prepares all contacts in the row 201. Magnet 210 closes a circuit for the horizontal operating magnet 226. This circuit is closed after the bar 209 has fully rotated and results in the connection of the link conductors 224 to the contacts in the vertical row 201 for a purpose to be described hereinafter. Magnet 210 also 8X-- tends the grounded conductor 227 throu h W its inner lower contact over conductor 228, through the winding of the multi contact relay 905. to battery. Relay 905 which is individual to the switch 200. operates and results in the connection of the conductors from the marker :tl'lrough to the frame of the selector switch 200.

lVith the frame connector 900 perated, relay 703 in the marker is energized in a cir cuit from battery, through the winding of said relay, opter left back contact 0t relay 710, conductor 730, through the frame connector 900, to ground over the conductor 922, as previously traced. Relay 7 03 at its normal contact opens th operating circuit of magnet 210, but before this occurs, said relay closes a substitute holding circuit for said magnet and also for relay 905, at the make-before-break contact of said relay 703.

The holding circuits may be traced from battery, through the winding and contact of magnet 210, conductor 228, and in parallel thereto from battery, through the winding and contact of relay 905, contact of relay 902, conductor 92 1, conductor 925, make contact of relay 703, and'thence over con-- ductor 727 as previously traced, to ground.

lVit-h the conductors of the horizontal link 22a connected to the contacts in the row 201, a circuit is closed for the relay 107 in the trunk circuit. The circuit for relay 107 may be traced from battery, through the winding thereof, conductor 113, contacts of the switch 200, conductor 229, through the frame connector 900, conductor 920, left contact of relay 703, to ground at the outer right contact of relay 708.

Operation 07' the district trunk connector.During the foregoing operations, the district trunk connector 901 is also being operated for the purpose of connecting the test relays 800 with the proper group of trunks outgoing from the districtselector 200. For starting the trunk connector 901 in operation, the relay 915 is energized in a circuit from battery, through the winding of said relay, conductor 927, outermost contact of group relay 712, conductor 728, outer right contact of relay 902, upper front contact of relay 909, to ground at the back contact of relay 908. Relay 915 operates the relay 91t in a. circuit from battery, through the left winding of relay 91%, right front contact of relay 915, back contact of relay 92S, upper back contact of relay 917, to ground at the back contact of slow-release relay 916. Relay 911 when operated, causes the operation of slow release relay 916 in a circuit from battery, through the winding of the latter relay, lower back contact of relay 917, left contact of relay 91-l, to the grounded conductor 921. Belay 916 operates and opens the energizing circuit of relay 91-l. Relay 91% being slightly slow-to-release, however, retains its ari'natures until relay 918 fully operates, atwhich time a locking circuit is closed as follows: battery, through the right winding and contact of relay 911, inner right back contact of relay 929, winding of relay 917, to ground at the front contact of relay 910. Relay 917 operates in this circuit and opens the circuit of relay 919, which subsequently releases. when relay 916 releases, the relays 91% and 917 are held energized in a circuit leading through the lower front contact of relay 917, left contact of relay 91st, to the grounded conductor 921. The multi-contact relay 910 is now operated in a circuit from battery, through its winding, outer right contact of relay 914;, upper front contact of relay 917 to ground at the back contact of relay 916. The 1nulticontact relay 912, which is individual to the group of trunks appearing in the vertical row 20% of the district lector 200, is operated in a circuit from battery, through its winding, conductor 9 50, contact of group relay 712, conductor 731, middle right contact of relay 91%, upper front contact of relay 917, to ground at the back contact of relay 916.

Testing Zia/cs and ZT'UHZJS at the district 51'0- Zccz0r.The marker is now prepared to proceed with a test of the selected group of trunks outgoing from the district scl-ctor 200 and also of the corresponding horizontal links. The right windings of the double wound test relays S01, S02, 803, etc., serve to test the trunks 230, 231, 232, 23 etc., in order. The left windings of these relays serve to test the corresponding horizontal links 205, 200, 207 and 208. The test circuit for the trunk 230 may be traced from battery, through the right winding of relay 801, through a back contact of relay S, conductor 813, right back contact of relay 5506, conductor 81%, conductor 1014:, through the trunk connector 901, conductor 931. to the sleeve conductor of the trunk 230. The test circuit for the corresponding link 20.5 may be traced from battery, through the lel't winding of relay 801, through a back contact of relay 808, conductor 815, through the frame connector 900, conductor 230, to the test conductor of the link 205. In a similar manner, test circuits for the remaining trunks of the group and of the correspomh ing links may be traced through the windings of the test relays 800.

It will be assumed that the trunk the last trunk of the group appearing Vertical row 201, and that the testing relay 805 relates to this particular trunk. it will further be considered that the n'ecedi' trunks in the group and the preceding lZm-..-, are busy in such combinations that their is no one of these trunks idle SilllttltilDOGH,l1 with the idle condition of its correspondii link. In other words. all of the te--t rela preceding the test relay 80.3 either has an energizing circuit for one or both of ts windings. The operated testing relays i. 802, etc., lock through their right \Tinxhn and contacts in a circuit over conductor .1. through the inner left hack contact of rela 708, to the grounded conductor 722.

At the instant the testing operation coniinenced. a circuit was completed for operating the vertical magnet 212 of the district selector 200. This magnet requires an appreciable interval in which to become operated, and consequentlyserves to measure the time within which the relays 800 are required to test the links and trunks and to assume their operated or non-operated ow dition accordingly. The circuit for the mag net 212 may be traced from battery, through the winding thereof, con-ductor 2537, tlllOit'il'll the frame connector 900, conductor 9232, conductor 933, contact of relay 712, conductor 729, contacts of the trunk connector 901, to the grounded conductor 921. When magnet 212 is operated, it. operates the relay 704 in a circuit from battery, through the winding of relay 704, normal contact oi'said relay, conductor 732, through theframe connector 900, conductor 238, to ground at the contact of magnet 212. The relay 704 locks through its inner right contact, through the inner left contact of relay 708, to the grounded conductor 722.

Relays 808 and 809 are now operated in circuits from battery through their windings, thence over conductor 818, inner left contact of relay 708, to the grounded coir ductor 722. Relays 808 and 809 disconnect the test relays 800 to preyent their subse quent operation. All of the energized relays, however, which were operated during the test, remain locked to the conductor 817. The relay 820 relating to the idle trunk 233 and link 208 is now operated in a circuit from batterythrough the winding of relay 812, win-ding of relay 820, left back contact of relay 805, thence through the left front contacts of relays 804, 803, etc, in series,

conductor 821, conductor 1015, through con tacts of the trunk connector 901, conductor 934, normal contacts of relay 705, cor'a-cts of relay 707, conductor 818, front contacts ofrelay 704-, thence over conductor 817, to ground as previously traced. Relay 812 also operates'in this circuit.

' The horizontal magnet is next operated by. means of a circuitfrom battery through the right winding of said magnet,

conductor 239, connector 900, conductor 935, middle left contact of relay 820, to the grounded conductor 817. Another circuit for magnet may he tra ed from battery through both windings thereof, thence yer conductor 234, through the connector 900,

conductor 936, next to the lower front con tact of relay v809, innermost left contact of relay 820, to grounded conductor 817. The closure of this latter circuit also results in placing a ground potential upon the test conductor of the horizontal link 208. life net 222 rotates the 218 and eifects connection from the trunk 102 through link 208 to the trunk 233..

'Returning to the point where relay 704 operates, it will be noted that this relay 'canses the release of the translator and I marker register relays. Relay 704 at its left contact removes ground potential from conductor 719, causing the release of relay 604 and consequently the release of relays 607, 612, 615 and636. Relay 704 also causesthe release of the operated relays of the registers 600,601 and 602. The operation of relay 704 also opens theholding circuitof relay 907'. l I During the time the translator relays are operated, acircuit has been closed for the relay 810 in the marker traceable from battery through the winding of said relay, conductor 819, to ground at the contact of the class relay 636. Relay 810 operates and locks to the grounded conductor 722.

Operation of the ofiice frame connector.- Since the selection has taken place at the district switch 200, it now becomes necessary to release the testing relays 800 to disassociate the marker from the district frame and to associate the marker with the oi'lice switch 300, in order to perform a similar testing operation thereat. The frame connector 1000 is started in operation by eergizing the relay 1007. The circuit for this relay may be traced from the grounded conductor 817, conductor 822, outer left con tact of relay 820, outer left contact of relay 810, conductor 823, through the district trunk connector 901, conductor 937, through the winding of relay 1007,. conductor 734, to battery at the normal contact of relay 711.

Since the district trunk connector 901 will Y presently release, the relay 1007 is locked in a circuit which leads through its winding and right front contact, conductor 1019, to the grounded conductor 722. Relay 1007 operates the relay 1004 in a circuit frombattery through the right winding of relay 1004, left front contact of relay 1007, left back contact of relay 1018, upper back contact of relay 1006, to ground at the back contact of slow-release relay 1005. Relay 1004 operates and causes the energization of relay 1005 in a circuit from battery through the winding of the latter relay, back contact of relay 1006, right contact of relay 1004, con

duc'tor 1019, to the grounded conductor 722. Relay 1005 opens the operating circuit of relay 1004. Relay 1004 being slightly slow to release, maintains its armatures until relay 1005 is fully operated, at which time the following circuit is completed: battery through theleft winding and contact of relay 1004, inner left back contact of relay 1020, winding of relay 1006, to ground at the front contact of relay 1005. Relay 1004 locks and relay 1006 operates in this circuit. The multi-contact relay 1002 is now operated in a circuit lea-ding through the outer left contact of relay 1004, to ground at the contacts of relays 1006 and 1005. I

Before proceeding to describe the operation of relay 1003, of the frame connector 1000, it may be well to discuss the release of the district frame and trunk connectors 900 and 901 which takes placebefore the relay 1003 is operated.

Release of the district frame and Mamie cmmccmmvVhen the district selector 200 is operated to extend the trunk 102 through to'the idle trunk 233, a circuit is closed for operating the release relay 707 in the marker. This circuit may be traced from battery, through the winding of said relay, conductor T35, right front contact of relay S20, thence over conductor 1021, through the trunk connector 001, conductor 235, thence through the district selector switch 200, slcere conductor of trunk 102, to ground the contact of slow-release relay 10G. clay TOT locks through its inner right con- :t contact of relay 708, to the inner left 0 inded conductor 722.

it may be noted at this time that the horizontal operating magnet 22-2 is also locked in a circuit from battery, through both its windings, thence through contacts of the switch 200, to the grounded conductor 115. Therefore, this magnet will remain 0perated after the marker, which furnishes the operating circuit therefor, becomes released. "l he release relay T07 operates the relay 708 in a circuit from battery, through the winding of relay 70S, inner right contact of relay T00, outer right front contact of relay T07, outer right front contact of relay T00, to ground at the outer right back contact of relay 702. Relay T00 prepares a holding circuit for itself from battery, through its winding and inner right contact, winding of relay T00, to the grounded condoctor T22. Relay T09, however, heing' shunted, d es not operate at this time.

The relay T0? in operating, renioyes ground potential from conductor 922, thereby causing the release of the frame connector 900 and the trunk connector 901 and all relays associated therewith. The yertical operatii'ig magnets 210 and 212 and the special horizontal operating magnet 220 are also released. Thus the marker is disasseciated from the district selector frame 200.

When relay T08 fully operated. it opens the holding circuit of relay 707. This latter relay becomes released as soon as its original operating circuit has been se ered by the trunk connector 001. Relay T0? in re- .ing, removes the shunt from the winding of relay T00 and this latter relay operates in series with relay 708 in tl e circuit above traced.

'l he relay T08 in operating, reinoyes ,ejround potential from conductor 817, whereby the operated test relays 800 are all released. llclay T00 operates the relay T10 in a circuit from battery, through the winding of relay T10, outer right front contact of relay T00. conductor T36, middle left contaat of relay S10, conductor S25, outer right back contact of relay T07, outer right contact relay 700. to ground attheouter right bacl; contact of relay T02. Relay T10 operates and closes a circuit for relay 711, traceable through the right contact of relay 710 to the ouniled conductor T22. lit the time relay TOT first operates, it opens the original holding circuit of relay 700. The relay 700, however, remains energized in a substitute holding circuit which may be traced from battery, through the winding and inner right contact of said relay, conductor 825, middle left contact of relay 810, conductor T36, outer right back contact of relay T09 (this latter relay being decncrgized at this particular time) to ground through the outer right contacts of relay 700 and relay T02. Before relay T09 can operate to open this substitute holding circuit, the original holding circuit is replaced by the release of relay TOT, which takes place prior to the operation of relay T00.

The. relays T10 and 711 in operating, place the llllilliel under the control of the otliee truul-z group relay 711-, so that the marker through the agency of the frame connector 1000 and the trunk connector 1001 can determine the selection and testing of the proper group of trunks outgoing from the oll ice frame 300.

l'i'hen ground is removed from conductor Si? as pre.'iously explained, relays T01, S00 and E 08 become deenergized. \Vhen the frame connector 000 is released as explained, relay 70 3 becomes d cenergized. Relay 70-1 l 1 before relay 711 operates and there- "11'0 battery potential is maintained on conuctor Till to hold relay 1007 after its original Lll'Clllt opened. hen the relay 70? operates, it opens the circuit of the district group relay T12 and this relay becomes released.

Operation. of the (if Eco frame and trunk connmaors.-Tlie relay 1011 is now operated to initiate the operation of the trunk connector 1001. The circuit for this purpose may be traced from battery, through the winding of said relay conductor 1022, contact of relay 711-, conductor T38, front contact of -el y 100i, upper front contactof relay 1000, to ground at the back contact of relay 1005, this latter relay ha ing deener isced upon the operation of relay 100G. llciay 1011 causes the operation of relays 1010. 1012 and 101 1 in the nanner hereinbe'iforc explained, resulting in the operati-on of in .ijicontact relay 1008. The multicontact re 1000 is now operated in a circuit from marthrough its winding, conductra' contact of relay T11, conduc- Tilt), right contact of relay 1010, to ground through the upper front contact of relay 101?), and the back contact of slow rclay 1012.

'lhe vertical magnet controlling the row oi contacts 301 in the oliice selector 300 is eni'sxgized by means of a circuit traceable lrom battery, through the winding of said magnet. upper back contact of relay 313, thence orer the tip conductor of the trunk =33, thron 200, left front contart of rela 107, through the sender selector 10S. conductor 112, through the connector e00, conductor 521, normal contact of relay 703. inner leftfront contact of relay 710, conductor 740, through the frame connector 1000, to the grounded conductor 1019. Magnet 309 operates the bar 308 and prepares the contacts in the vertical row 301. Magnet 309 also extends the circuit above traced through its contact and the winding of multi-contact relay 1003, to battery. Relay 1003 operates and completes a circuit for relay 703 traceable from battery, through the winding of the latter relay, outer left front contact of relay 710, conductor 741, through contacts of the connector 1000, to the grounded conductor 1019. Relay 703 opens the energizing circuit of magnet 309 and relay 1003, but at its make-before-break contact completes a holding circuit traceable from battery, through the winding and contact of magnet 309, and in parallel from battery through the winding and contact of relay 1003, contact of relay 1002, conductor 924, conductor 925, contact of relay 703, inner left front contact of relay 710, to ground as above traced over conductor 740.

Testing the trunks at the ofiice switch.- The marker is prepared to make a test of the group of trunks appearing in the vertical row of contacts 304 at the office-switch 300. This particular group of trunks is selected under the control of the ofiice trunk group relay 714. The selection consists in operating the vertical magnet 311 in a circuit from battery, through the winding of said magnet, conductor 315, thence through the frame connector 1000, conductor 1024, conductor 038, contact of tor 742, through the trunk connector 1001, to the grounded conductor 1010. The magnet 311 operates the vertical bar 312, preparing all contacts in the vertical row 304.

The testing operation takes place in substantially the same manner as that described in connection with the district selector switch 200. The testing relays 800 serve to test the successive trunks and the associated links in the ofiice switch 300. The trunks 316, 317 and 318 may be considered as the last trunks in the group. Relay 805 relates to the trunk 318; relay 804 relates to the trunk 317, and the relay for the trunk 316 is not shown. The preceding relays 801 to 803 may relate to preceding trunks in the group. It will be assumed that the trunk 317 is the first one in the group to be idle simultaneously with the idle condition of its associated link 306. Accordingly, the relay 804 remains in a deenergized condition while all preceding test relays are operated. It will be understood that, analogous to the manner in which the testing relays perform the test during the operation of the vertical magnet- 212 of the district selector, these relays also perform a similar test during the period the vertical magnet 311 of the office switch is being energized. Accordingly, by the time relay 714, conduc the magnet 311 is operated in the circuit above traced, the relays 800 have assumed their set condition. When the magnet 311 is fully operated, it operates the relay 704 the marker by means of a circuit from battery, through the winding of said relay, normal contact of said relay, conductor 732, conductor 743, through the frame connector 1000, conductor 319, contact of magnet 311, to ground. Relay 704 looks in a circuit through its winding and inner right front contact, inner right front contact of relay 711, to the grounded conductor 722. Relay 704 opcrates the relays 808 and 809 in circuits from battery, through the windings of these latter relays in parallel, conductor 818, inner right contact of relay 704, to ground as just traced. Relay 826 is operated in a circuit from battery, through the winding of relay 812, thence through the winding of relay 826, left back contact of test relay 804, thence through the left front contacts of the preceding operated test relays, conductor 821, through the trunk connector 1001, conductor 1026, conductor 934, normal contacts of relays 705, normal contacts of relay 707, right front contact of relay 704, to ground through the inner right front contact of relay 711 by way of conductor 722. Relay 826 operates and prepares for operation, the horizontal magnet 320.

The operating circuit for the horizontal magnet 320 is now completed from battery, through the right winding of said magnet, conductor 321, through the frame connector 1000, conductor 1025, contact of relay 826, to the grounded conductor 817. It will be noted that conductor 817 is grounded through the inner right front contact of relay 711. Ground potential on this conductor also serves to hold the operated test relays 800 in the manner hereinbefore described. The magnet 320 rotates the horizontal bar 322 and completes the connection of the trunk 233 through the switch 300 to the selected idle trunk 317. Relay 313 is operated in a circuit from battery, through its winding, contact of switch 300, conductor 323, through the connector 1000, conductor 1027, inner front contact of relay 809, inner left contact of relay 826, conductor 822, to the grounded conductor 817. Relay 313 operates and closes a locking circuit for itself and also for the horizontal magnet 320. The locking circuit may be traced from battery, through both windings of magnet 320, con tacts of switch 300, and in parallel thereto from battery through the winding and con tact of relay 313, sleeve conductor 324, through contacts of the switch 200 to the grounded sleeve conductor 115. The relay 313 completesthe tip and ring conductors of the trunk 233 and opens the energizing circuit of the vertical magnet 309.

Release of the ofice fmme and trunk 00%- heaters and of the marlrer.-The connection having been extended through the district and otiice switches, the marker is no longer required and may now be released and returned to the common use 01 other lines. For this purpose, the release relay 70? is reoperated in response to the completion of the connection through the otiice switch 300. The circuit may be traced from battery, through the winding of relay 707, conductor 7 35, right front contact of relay S26, conductor 827,- through the trunk connector 1001, conductor 326, through contacts of the switch 2-300, to ground over conductor 323 as previmisly traced. Relay T07 operates and locks temporarily through the inner right contact of relay T11. Relay 70? at its outer right back contact, opens the holding circuit of the rela 700 which releases. Relay 700 in releasing, removes ground from the conductor 722, thereby causing the release of the otlice frame connector 1000, the oflice trunl: connector 1001, the relays associated therewith, the vertical magnets 309 and S11, and the test relays S00, together with the operated relays of the marker.

Prior to the time that the marker is disassociated tromthe sender as will presently be described, an indication is transferred 'lrom the marker to the sender, notifying the latter mechanism that connection has been completed through the district and otiice switches. This indication consists in operating the relay all in the sender by means of a circuit completed at the contact or relay 812. This circuit may be traced in detail from battery, through the winding of relay 414:, conductor e25, through the connector 500, conductor 5L3, outer right contact of relay 711, conductor 7-11, to ground at the contact of relay 812. This circuit is not closed until the relay 812 operates a second time; namely, in series with the relay 8% preparatory to the operation of the oliice switch 300. The reason why said circuit is not completed when relay 812 operates the first time, namely in series with the relay 820, is because the relay 711 has not been energized at this time. Relay 11 locks through its left contact to the grounded conductor 121.

The marker may now be discharged "from the sender. which release occurs as soon as the relay 700 becomes deenergized. Relay T00 in deenergizing as previously described, removes ground from conductor 718, and thereby opens the holding circuit of relays 501 and 502. Relay 2 in releasing, causes the release oi relays 503, 509, 510, 511 and 508. Thus the marker is disassoeiated from the register sender.

From this point on, the connection may proceed in any suitable manner according to the class of t e call concerned. It, for in stance, the connection is one extending to a distant ofiice equipped with'call indicators, the sender shown in the drawing may adjust itself in such a manner as to transmit inipulses to the distant oliice to set the call indicator therein. jitter the sender has completed its function, a circuit may be completed "for operating the sender release relay r10. Relay 1-10 opens the holding circuit of the impulse relay 100, which releases the slow relay 401. glelay 4:01 in turn releases the holding relays 102 and 110. These relays remove ground potential from the hold ing conductors to permit the release ol the various energized relays in the sender.

The sender in releasing, a :o causes the releaf e 01 the sender selector v.tch 10b and the relay 10, whereby the subscribcns line is completed through to the repeating coil 1023. The manner in which the sender may cause the transmission of impulses to a (llitant o'tlit-e to further extend the connection or to operate a call indicator, and also the manner in which the sender releases, Following the completion 01 its functions, are shown and described in general. in the patent. to S. B. li illiams, No. 1,517,331, granted Dec. 2, 1921;.

Jill trim/rs busy at the district .s-cZc Zo/'.- it will be assumed that when the marker makes a test of the group of trunks out- )ing from the district selector switch, all of these trunks are busy. Under such a condition it is desirable to release the marlccr trcni the sender and to re-associate lhe sender with the same or another marker for the purpose of making a new test ol the trunks to ascertain whether or not, in the meantime, one has become idle.

Since all the trunks are busy. a circuit is closed for operating the busy relay T05 and may be traced from battery, through the left winding of said relay, C(il'ltlllt'itd' 710. through contacts of the district trunk connector 90]., conductor 9 conductor "Fl-. thence through the left front contacts oi' all the test relays in series, to conductor R31, thence to conductor 1015, through the trunk connector 901, conductor G ll. normal con tact of relay T05. normal contact of relay 707, inner right contact of relay 701-. to the grounded conductor 817. Relay 705 at its inalse-betore-breal; contact, opens the circuit just traced and closes a holding ircuit as follows: battery. through its right w1nding and make contact, to ground as above traced. Relay T05 operates the rel 12? in the sender. The circuit for this 17111171)".- may be traced from battery, through the winding and normal contact ot relay lei. conductor 42?}, through the coi'inector Zoo. conductor 521, inner left contact oi" relay 705, to the grounded conductor 7 1a}- lay operates and lOCliS through its winding and inner left conta -t to the grounded conductor e221. Belay 1:2 also operates the 

